Vat dye and process of making same.



UNITED STATES PATENT OFFICE.

AUGUST LEOEOLD LASKA, OF OFFENBACHON-TIIIE 1-MAIN, Gil")IlEtMANY, ASSIGNOR TO CHEMISCHE FABRIK GRIESHEIM ELEKTRON, OF FRANKFOBTON-THE-MAIN, GER- MANY, A CORPORATION.

' VAT DYE AND rnocnss or MAKING- SAME.

No Drawing.

To all whom it may concern:

- -Be it known that I, AUGUST Luororln The new vat dyestuffsare produced by acting with oxidizing agents upon azodyestuffs, obtained by -combining.(5-diazo compounds of the anthraquinone series with 5-- amino derivatives of the naphthalene series. Consequently ortho-amino-azo' dyestuffs ar oxidized of the general formula:

A i da-15 111,,

wherein A means an anthraquinone radical and B a naphthalene radical. a

The oxidizing 'processmay be performed either in acid or alkaline solution. The simplest representative of these bodies is the product of oxidation of the azo dyestuft' from 5 diazo-anthraquinone and fi-naphthyh amin, whichmay be-called c-b-naphthyleneaccording to the nomenclature used by Zincke (Bem'ohte der Demise-hen; Obemischen Gesellschaft XVIII, page In carrying out the new process practically I can proceed as follows, parts being by weight. I

Example I: 23 parts of li-aminoanth'raquinone are dissolved in 100 parts of concentrated sulfuric acid. The solution is diluted with ice and diazotized by means of 7 parts of sodium nitrite dissolved in 100 parts of water. -The diazo solution is added to a slightlyacid solution containing 15 parts of Specification of Letters Patent.

li-naphthylamin. The formation of dyestuif is completed by addition ofsodium acetate, sodium carbonate or caustic soda lye. The dark violet precipitated azo dyestutf is filtered off washed out and dried. 100 parts of the thus obtained azo dyestufi' are dissolved in 500 parts of nitrobenzene and oxidized at about 120 C. by successive addi-' Patented Feb. 6, 1912.

Application filed May 4, 1911. Serial No. 624,999.

tion of a solution of about 100 parts of sodium dichromate in 500 parts of glacial acetic acid. The product of reaction partially separates .from the still warm solution in shape of yellow crystals and is almost completely precipitated when the solution has cooled down. i The crystals are filtered off and Washed with alcohol. The thus obtained a (L naphthylene pseudo azi'mi'no-[fianthraquinonyl can be obtained absolutely pure by recrystallizing it from nitrobenzene. The melting point of the recrystallized product is about 300 'C. It is insoluble in the most organic solvents at atmospheric temperature; it dissolves in concentrated sulfuric acid witlr brownish-orange to redbrown color and is precipitated from this so; lution by addition of water in shape of yellow flakes. With alkaline hydrosulfite solution a brown-violet vat is obtained, from which cotton is dyed dark-brown violet, shades, which by oxidation are turned into yellow-ones of very good fastness to washing and chlorin.

Example II: 45 parts of fi-aminoanthraquinone arediazotized as set forth'in Exam- .ple-I and combined with 17 parts of 2 :G-naphthylene-diamin. -The insoluble black violet azo dyestuff is oxidized as described in Example I. The thus obtained product of re-- action is a yellow-brown powder, which dissolves in concentrated sulfuric acid with brown color from which solution'it is precipitated by diluting it with water in shape of yellow-brown flakes. The dyestuff dyes cotton brownish-yellow-shades. In this example two molecules of 'diazotized' ti-aminoanthraquinone are combined with one molecule 2.6naphthylenediamin.

Example III: 60'parts of 2:6-diaminoanthraquinone are dissolved in 200 parts of concentrated sulfuric acid 66 B., diluted with ice and diazotized by means of 35 parts of sodium nitrite dissolved in the necessary quantity 1 of water.

compound is combined with 75 parts of ioo The tetrazo S-na'phthylamin. The dyestuflf is oxidized substantially as described in Example I. The product of oxidation, containing the azimino radical twice is a brown-yellow powder, which dissolves in concentrated sulfuric acid with yellowish-brown color. The dyestufi' dyes cotton orange-yellow shades. In this example one molecule of tetrazotized 2.6-diaminoanthraquinone is combined with two molecules [S-naphthyL amin, a

Example IV: 60 parts of 2:6-diaminoanthraquinone are diazotized substantially as described in Example III and combined with 120 parts of the sodium salt of 2:6-napht-hylaminsulfonic acid. The diflicultly soluble dark violet azo dyestuif is oxidized in alkaline solution by means of sodium hypochlorite. The thus obtained azimino bodyis a brownish yellow powder, soluble in concentrated sulfuric acid with like color. By pouring this solution into water the dyestufi' is precipitated in shape of yellow flakes. It dyes cotton bright yellow shades.

In analogous manner may be performed the oxidation of azo dyestuifs from other derivatives of the fi-aminoanthraquinone for instance from chloroor nitro-ll-aminoanthraquinone.

Instead of the oxidizing agents given in the examples others may be used.

Now what I claim and desire to secure by Letters Patent is the following:

1. The process of manufacturing vat dyestufls consisting in acting with oxidizing agents upon ortho-amino-azo dyestufi's of the general formula:

A =N R.N H,, wherein A means an anthraquinone radical and R a naphthalin radical.

2. As a new article of manufacture the vat dyestuffs obtained by oxidation of the azo dyestutf from Q-diazo-anthraquinone and fi-naphthylamin, which dyestufi dissolves in concentrated sulfuric acid with brownish-orange, to red-brown color, being precipitated from this solution in shape of yellow flakes by addition of Water, yielding with alkaline hydrosulfite solution abrownviolet vat, from which cotton is dyed darkbrown violet shades, which by oxidation are turned into yellow ones.

In testimony that I claim the foregoing as my invention, I have signed my name in presence of two witnesses, this 21st day of April, 1911.

AUGUST LEOPOLD LASKA.

Witnesses 'HERMANN IVEIL, CARL GRUND. 

